The economic stimulus bills before Congress contain a $140 billion boost for education – and most of it would be used to more than double federal spending on America's public schools over the next two years.

The legislation is part short-term stimulus, intended to create jobs via school renovation projects and to prevent massive teacher layoffs in the face of state and local budget deficits. But it is also part social policy, channeling federal dollars to programs designed to improve the academic achievement of low-income and other struggling pupils. Indeed, funding for the major program serving students from poor families would get an extra $13 billion through 2010, an amount nearly as high as the current annual budget.

President Obama has indicated he sees such spending as an investment in students that will pay an economic benefit in the long term. But whether the infusion of cash will narrow stubborn achievement gaps – a top goal of US education law – is a matter of opinion.

At the very least, supporters argue, the stimulus dollars will prevent a backward slide.

"Poor and minority kids get hit first and hardest in state budget cuts," says Amy Wilkins, vice president for government affairs at The Education Trust, a Washington nonprofit. "This federal money could help a lot and could allow schools to continue the momentum they are just now beginning to build up on gap-closing."

Skeptics argue that the US government should not pour so much money into public schools but that, if it does, it should attach some strings to ensure that states and localities change their education systems. They should be forced, in particular, to wean themselves from ineffective practices and unsustainable labor contracts, critics say.

Other provisions aimed at at-risk students range from child care and preschool for low-income families to extra support for homeless students.

"Poverty is a factor that most affects achievement levels in the schools, and to drive dollars into the schools that need it the most ... will be a major boost and will allow the achievement levels to grow," says Daniel Domenech of the American Association of School Administrators in Arlington, Va. He warns, however, that districts will still have to make tough budget choices. "Layoffs will still happen; this is going to help, but it's not 100 percent making up the district shortfalls."

Some of the money gives new leverage to the US Department of Education. Both the House and the Senate bills, for instance, would use $15 billion of the state stabilization funds for grants to states and districts that have made progress in improving testing, creating data systems to track students' achievement, and ensuring that excellent teachers are placed in high-needs districts (as opposed to the current trend of staffing those schools with the least-experienced teachers). The House version also includes nearly $500 million in additional funds for such goals and for linking teacher bonus pay to their students' achievement.

Education-reform advocates such as Ms. Wilkins support these incentives.

"Restoring the status quo isn't good enough for poor kids, because they weren't being educated adequately prior to the financial crunch," she says.

The impulse to attach strings to the new money loses sight of the primary purpose of the stimulus bill, says Jack Jennings, president of the Center on Education Policy, a public-school advocacy group in Washington. "The more people want to put conditions on this money, the slower the money is going to be spent," he says. "If we go into a depression, you're not going to close the achievement gap.... You [won't] have the teachers there to teach."

The extra special-education funding would help ease what states and localities have long seen as an unfair burden. When the original special-education law passed in 1975, the US government promised to pay 40 percent of the costs, but it never has. The feds spent nearly $11 billion on special education in fiscal year 2008, about 17 percent of the total cost. In past years, the federal share has run even lower.

"The federal government has essentially reneged," says Doug Fuchs, an education professor at Vanderbilt University in Nashville, Tenn. Studies of special-ed achievement levels haven't shown strong improvement over the past few decades, he adds.

While needed, the special-education funding alone is not the key to improved student performance, says Lou Danielson, managing director at the American Institutes of Research and a former special-education staffer in the US Department of Education. "The fact that kids with disabilities were included as a subgroup [for school accountability] in No Child Left Behind has really focused, probably more than anything, attention on [their] academic performance," he says. So how the bill is reauthorized by Congress, and whether those requirements continue, will be "critically important."

How temporary some of this boosted education spending will be is another question. Some supporters and critics alike suggest it will be hard for the government to pull back once the economy recovers, because it would be seen as removing programs for students in need.

"We are entering a new era for federal funding of many things, but education in particular," says Edward Kealy of the Committee for Education Funding, an education coalition in Washington. "Once you've made this rationale that education [is] an essential component in response to an economic crisis ... you've given a rationale that it never had before."